Thread tensioning device for thread processing machines and devices



Sept 26 1961 J. JENTSCHMANN 3 THREAD TENSIONING DEVICE FOR THREAD 'OOL946 PROCESSING MACHINES AND DE Filed July 14, 1958 INVENTOR Jakob Jenfschmann ATTORNEYS certain parts shown in elevation.

rial is fastened to United States Patent Oifice 3,001,946. Patented Sept. 26, 1961 Filed July 14, 1958, Ser. No. 748,419

1 Claim. (CL 242-150) The present invention relates to a thread tension device for sewing machines, spinning machines, rewinding machines, weaving machines and other thread processing machines and devices, comprising two friction discs flexibly pressed against each other, wherein the power for compressing the friction discs is at least partially produced by a magnetic field.

While in known thread tension devices the tension with which the two guiding discs are pressed against each other is produced by threaded or screw parts, an object of the present invention is to provide a force which is at least partially produced by a magnetic field, preferably by the repulsive force of magnets having like poles located opposite an air gap.

- With the above and other objects in view which will become apparent from the detailed description below, one embodiment of the invention is shown in the drawings wherein the figure is a cross-sectional view with The cylinder block 1 consrstrng a bracket 3 by means of the bolt 2. said bracket being secured to the machine body 4 by the bolt 17. By means of the bolt 2, a thread guide 5 is supported through the aperture 15 of which the thread 6 is passed to two thread friction discs 7 and 8.

The two annular friction discs 7 and 8 are located loosely on the stem 9 of a bolt 16 screwed into the block 1 and are positioned between the head disc 10'of the bolt 16 and a disc 11 also placed loosely on the stem 9.

For the production of tension, i.e. for compressing the disc 11 against the bolt head 10 and compressing the discs 7 and 8 there are provided pairs 12a, 12b and 13a, 13b

- of permanent magnets which are placed in the bores 14 of the block 1 so that they have like poles opposite one another. When the bolt 16 is screwed further into the block 1, the air gap between the oppositely positioned like poles S of the permanent magnets narrows and the 45 2,843,336 Herbst of non-magnetic mate- I repulsive force and thereby the thread tensioning force increases progressively.

By a more or less deep screwing of the bolt 16 into the block 1, the width of the air gap between the magnets changes.

Since the repulsive force of such a system with a large air gap is relatively small and at a reduction of the air gap towards zero increases progressively steep, such a system can fulfill better the essential-practical requirements, namely a relatively fast abutting of the friction discs under normal condition and a fast return of the discs into normal distance after a separation by a thickening of the thread, than if the braking force were accomplished by threaded elements.

The principle according to the present invention can be also put into practice by means of'electromagnets, whereby for influincing the tension the induction current can be changed for example.

It is thought that the invention and its advantages will be understood from the foregoing description and it is apparent that various changes may be made in the form. construction and arrangement of the parts without departing from the spirit and scope of the invention or sacrificing its material advantages, the form hereinbefore described and illustrated in the drawings being merely a preferred embodiment thereof.

I claim:

A thread tensioning device magnetic material, a bolt secured having a bolt said bolt, two

comprising a block of nonin said block, said bolt friction discs placed loosely between said bolt head and said annular .disc, said block having bores therein parallel to said bolt, a pair of magnets in each of said bores with like poles opposite one another with an intervening air gap so that when said bolt is threaded into said block the size of said air gap, is varied to thereby vary the tensioning force exerted by said discs upon a thread therebetween.

References Cited in the file of this patent UNITED STATES PATENTS 2.281.204 Raymond Apr. 28. 1942 2,614,773 Arnrnerall Oct. 21, 1952 July 15, use

head, an annular disc loosely mounted on 

